Masih Banyak Misteri di Alam Semesta
Adalah pemenang hadiah Nobel Fisika tahun 2011 Prof. Brian Schmidt berkenan datang ke Indonesia menghadiri perhelatan ilmiah ICMNS yang diadakan di ITB setiap tahun. Beliau datang selaku qey note speaker serta berkenan juga memberikan kuliah umum yang diperuntukkan untuk para audiens umum seperti para guru dan siswa sekolah menengah serta siswa dan masyarakat umum pemerhati fisika dan astronomi modern.
Alhamdulillah Bloger berhasil menghadiri acara tersebut yang berlangsung pada hari minggu 2 November 2014 jam 3.30 sore yang di langsungkan di Aula Barat ITB yang memang biasa digunakan untuk tempat tampilnya sejumlah tokoh penting membicarakan berbagai topik aktual di ITB. Meskipun semenjak hari Jum'at 2 hari sebelumnya kondisi fisik bloger kurang fit dan mengalami demam panas, namun bloger tetap bela-belain hadir di seminar tersebut. Bahkan tepat di hari acara seminar berlangsung panas dalam tersebut berubah menjadi radang tenggorokan yang cukup serius sehingga Blogger tidak dapat menelan nasi sehingga hanya bisa memakan makanan yang berkuah serta minum susu.
Salah satu kebahagiaan yang Blogger rasakan meskipun hanya selaku guru di sekolah menengah ini adalah Blogger sering punya kesempatan untuk dapat melihat secara langsung dan bahkan dapat bertatap muka dan berkenalan dengan para Ilmuwan Fisika yang memang keseharian mereka bertungkus lumus dengan riset ilmiah di tapal batas terakhir perkembangan fisika kontemporer. Kesempatan seperti ini jelas jarang di miliki oleh rekan-rekan penulis yang mengajar sains di sekolah menengah. Beberapa di antara mereka penulis kenal secara pribadi serta pernah duduk dibangku kuliah mengikuti kuliah mereka, di antaranya Dr. rear. nat. M. Farchani Rosyid, Mirza Satriawan PhD, Prof. Dr. Bobby Eka Gunara, Prof. Dr. Freddy Zen, Prof. Dr. Triyanta, Dr. Husin al Attas, dan lain-lain. Lain kesempatan Blogger akan mengulas sedikit soal para Ilmuwan dan Guru Besar Fisika ini. Yang jelas para Ilmuwan ini mempunyai banyak kelebihan dan sisi positif yang menurut Blogger sangat penting di ambil untuk menjadi bahan pertimbangan bagaimanakah selayaknya sebuah kurikulum dan pembelajaran fisika dibangun agar menghasilkan tokoh-tokoh seperti mereka. Bagaimana menciptakan siswa-siswa yang punya mentalitas dan kecendrungan "pembelajar" serta "periset seperti mereka".
Artinya dengan merasakan secara langsung semangat, kegairahan dan visi mereka soal sains kita akan memperoleh suatu materi yang sangat banyak soal pendidikan sains di sekolah menengah ketimbang kita duduk di bangku kuliah yang berkutat dengan teori pendidikan. Karena kita tahu persis cara dan metode mereka berhasil sedangkan metode dan teori didaktik yang terkadang sangat rumit dan serba berbau formalitas kebijakan sangat sulit diuji validitas keberhasilannya. Penulis teringat dengan saran guru penulis waktu di UGM Dr. rear. nat M. Farchani Rosyid bahwa untuk mengerti cara buat patung, kita sebaiknya belajar kepada seorang pembuat patung sejati, jangan belajar kepada, katakanlah misalkan pada penjual patung. Boleh jadi sang penjual patung tampak mengesankan argumentasinya soal patung tersebut, namun membuat patung yang sebenarnya belum tentu mereka bisa. Salah satu kesempatan cukup langka juga untuk lebih merasakan "aura" saintifik sejati adalah hadir di perkuliahan yang dibawakan langsung oleh seorang pemenang hadiah Nobel.
Brian Paul Schmidt AC, FRS (lahir 24 Februari 1967) adalah a Distinguished Professor, Australian Research Council Laureate Fellow and astrophysicist di The Australian National University Mount Stromlo Observatory dan Research School of Astronomy and Astrophysics dan beliau dikenal dengan risetnya soal supernova (supernovae) yang dimanfaatkan sebagai perunut kosmologis. Baru-baru ini beliau menjabat Australia Research
Council Federation Fellowship dan dipilih dalam keanggotaan Royal Society di tahun
2012.[2] Schmidt berbagi Shaw Prize in Astronomy 2006 dan Nobel Prize in Physics 2011 dengan Saul Perlmutter dan Adam Riess yang berhasil memberikan bukti bahwa pengembangan alam semesta berlangsung dipercepat (expansion of the universe is accelerating).
Berdasarkan amatan mereka, semenjak alam semesta mengembang setelah BigBang, pengembangan berlangsung dipercepat. Sebelum temuan tersebut, para Fisikawan memperkirakan bahwa semestinya laju pengembangan akan diperlambat.
Temuan ini mengarahkan kepada penerimaan luas akan teori energi gelap (dark energy), yaitu suatu teori yang memprediksikan adanya gaya misterius yang menolak gravitasi. Pengukuran astrofisika memperkirakan bahwa energi gelap 74 persen dari semua kandungan alam semesta.
Namun lebih dari satu dekade sesudah temuan bernilai hadiah Nobel ini, para ilmuwan masih berkutat dengan kajian apakah energi gelap itu sejatinya dan berusaha memecahkan persoalan yang disebut-sebut para ahli sebagai "persoalan paling penting" dalam sejarah fisika modern.
Berikut penjelasan Physics World
Meskipun demikian, semenjak pertengahan tahun 1980an sederetan pengamatan telah dilakukan yang mana hasilnya nampaknya tidak sesuai dengan teori standar. Hal ini menyebabkan sejumlah orang mengusulkan membangkitkan kembali konsep lama yang di sesali Einstein yaitu Konstanta Kosmologi agar supaya menjelaskan data baru ini lebih baik.
Konstanta ini pertama kali diperkenalkan oleh Einstein di tahun 1917 untuk mengimbangi gaya tarik gravitasi, karena beliau percaya akan alam semesta yang bersifat statik. He considered it a property of space itself, but it can also be interpreted as a form of energy that uniformly fills all of space; if lambda is greater than zero, the uniform energy has negative pressure and creates a bizarre, repulsive form of gravity. However, Einstein grew disillusioned with the term and finally abandoned it in 1931 after Edwin Hubble and Milton Humason discovered that the universe is expanding.
In 1987 physicists at the Lawrence Berkeley National Laboratory and the University of California at Berkeley initiated the Supernova Cosmology Project (SCP) to hunt for certain distant exploding stars, known as type Ia supernovae. They hoped to use these stars to calculate, among other things, the rate at which the expansion of the universe was slowing down.
Deceleration was expected because in the absence of lambda, many people thought that "ΩM", which is the amount of observable matter in the universe today as a fraction of the critical density, was sufficient to slow the universe's expansion forever, if not to bring it to an eventual halt.
In 1998, after years of observations, two rival groups of supernova hunters – the High-Z Supernovae Search Team led by Schmidt and Riess and the SCP led by Perlmutter – came to the conclusion that the cosmic expansion is actually accelerating and not slowing under the influence of gravity as might be expected.
The two teams came to this conclusion by studying type Ia supernova where they found that the light from over 50 distant supernovae was weaker than expected. This was a sign that the expansion of the universe was accelerating.
In order to account for the acceleration, about 75% of the mass-energy content of the universe had to be made up of some gravitationally repulsive substance that nobody had ever seen before. This substance, which would determine the fate of the universe, was dubbed dark energy.
It is now thought that dark energy constitutes around 75% of the current universe, with around 21% being dark matter and the rest ordinary matter and energy making up the Earth, planets and stars.
"The findings of the 2011 Nobel Laureates in Physics have helped to unveil a universe that to a large extent is unknown to science," stated the Academy. "And everything is possible again."
"My involvement in the discovery of the accelerating universe and its implications for the presence of dark energy has been an incredibly exciting adventure," says Riess. "I have also been fortunate to work with tremendous colleagues and powerful facilities. I am deeply honored that this work has been recognized."
Turner adds that before the discovery, cosmology was in some disarray with astronomers having a model of the universe based on cold dark matter and inflation, but with not enough matter to make the universe flat – a key prediction of inflation.
"Dark energy and cosmic acceleration was the missing piece of the puzzle," says Turner. "Moreover, in solving one problem, it gave us a new problem – what is dark energy? I think that is the most profound mystery in all of science."
Robert Kirshner from Harvard University who supervised both Schmidt and Riess when they were PhD students says the decision by the Nobel committee is "great" as it will mean "no more waiting". "We did a lot of foundational work at Harvard and my postdocs and students made up a hefty chunk of the High-Z Team," says Kirshner. "[Riess] did a lot after the initial result to show that there was no sneaky effect due to dust absorption and that, if you look far enough into the past, you could see that the universe was slowing down before the dark energy got the upper hand, about five billion years ago."
Kirshner adds that Perlmutter is also "very deserving" of the prize. "[Perlmutter] was persistent even when his programme was moving slowly and, despite getting a contrary result in 1997, was convinced of cosmic acceleration during 1998 by comparing his own extensive data set of distant supernovae with the nearby supernovae measured by the group in Chile."
Peter Knight, president of the Institute of Physics, which publishes physicsworld.com says the work has "triggered an enormous amount of research" on the nature of dark energy. "These researchers have opened our eyes to the true nature of our universe. They are very well-deserved recipients," says Knight.
Schmidt was born in Missoula, Montana, in 1967. He graduated from the University of Arizona in 1989 and received his PhD from Harvard University in 1993 on using type II Supernovae to measure the Hubble Constant. During postdocs at Harvard, Schmidt, together with Nicholas Suntzeff from the Cerro Tololo Inter-American Observatory in Chile, formed the High-Z Supernovae Search Team. In 1993 Schmidt then went to the Harvard-Smithsonian Center for Astrophysics for a year before moving to the Australian National University where he is currently based.
Riess is also a former member of the High-Z Supernovae Search Team where he lead the 1998 study that reported evidence that the universe's expansion rate is now accelerating. He was born in Washington, D.C in 1969 and graduated from The Massachusetts Institute of Technology in 1992. Riess received his PhD from Harvard University in 1996 researching ways to make type Ia supernovae into accurate distance indicators. In 1999 he moved to the Space Telescope Science Institute at Johns Hopkins University.
Salah satu kebahagiaan yang Blogger rasakan meskipun hanya selaku guru di sekolah menengah ini adalah Blogger sering punya kesempatan untuk dapat melihat secara langsung dan bahkan dapat bertatap muka dan berkenalan dengan para Ilmuwan Fisika yang memang keseharian mereka bertungkus lumus dengan riset ilmiah di tapal batas terakhir perkembangan fisika kontemporer. Kesempatan seperti ini jelas jarang di miliki oleh rekan-rekan penulis yang mengajar sains di sekolah menengah. Beberapa di antara mereka penulis kenal secara pribadi serta pernah duduk dibangku kuliah mengikuti kuliah mereka, di antaranya Dr. rear. nat. M. Farchani Rosyid, Mirza Satriawan PhD, Prof. Dr. Bobby Eka Gunara, Prof. Dr. Freddy Zen, Prof. Dr. Triyanta, Dr. Husin al Attas, dan lain-lain. Lain kesempatan Blogger akan mengulas sedikit soal para Ilmuwan dan Guru Besar Fisika ini. Yang jelas para Ilmuwan ini mempunyai banyak kelebihan dan sisi positif yang menurut Blogger sangat penting di ambil untuk menjadi bahan pertimbangan bagaimanakah selayaknya sebuah kurikulum dan pembelajaran fisika dibangun agar menghasilkan tokoh-tokoh seperti mereka. Bagaimana menciptakan siswa-siswa yang punya mentalitas dan kecendrungan "pembelajar" serta "periset seperti mereka".
Artinya dengan merasakan secara langsung semangat, kegairahan dan visi mereka soal sains kita akan memperoleh suatu materi yang sangat banyak soal pendidikan sains di sekolah menengah ketimbang kita duduk di bangku kuliah yang berkutat dengan teori pendidikan. Karena kita tahu persis cara dan metode mereka berhasil sedangkan metode dan teori didaktik yang terkadang sangat rumit dan serba berbau formalitas kebijakan sangat sulit diuji validitas keberhasilannya. Penulis teringat dengan saran guru penulis waktu di UGM Dr. rear. nat M. Farchani Rosyid bahwa untuk mengerti cara buat patung, kita sebaiknya belajar kepada seorang pembuat patung sejati, jangan belajar kepada, katakanlah misalkan pada penjual patung. Boleh jadi sang penjual patung tampak mengesankan argumentasinya soal patung tersebut, namun membuat patung yang sebenarnya belum tentu mereka bisa. Salah satu kesempatan cukup langka juga untuk lebih merasakan "aura" saintifik sejati adalah hadir di perkuliahan yang dibawakan langsung oleh seorang pemenang hadiah Nobel.
Berdasarkan amatan mereka, semenjak alam semesta mengembang setelah BigBang, pengembangan berlangsung dipercepat. Sebelum temuan tersebut, para Fisikawan memperkirakan bahwa semestinya laju pengembangan akan diperlambat.
Temuan ini mengarahkan kepada penerimaan luas akan teori energi gelap (dark energy), yaitu suatu teori yang memprediksikan adanya gaya misterius yang menolak gravitasi. Pengukuran astrofisika memperkirakan bahwa energi gelap 74 persen dari semua kandungan alam semesta.
Namun lebih dari satu dekade sesudah temuan bernilai hadiah Nobel ini, para ilmuwan masih berkutat dengan kajian apakah energi gelap itu sejatinya dan berusaha memecahkan persoalan yang disebut-sebut para ahli sebagai "persoalan paling penting" dalam sejarah fisika modern.
 |
| Astrofisikawan Saul Perlmutter menganalisis kecerlangan yang berasal dari supernova, seperti yang ditunjukkan oleh gambar ini, untuk mengukur seberapa cepat alam semesta mengembang. |
Mengembang Melawan Gravitasi
Hanya 25 tahun yang lalu sebagian besar ilmuwan percaya bahwa alam semesta dapat digambarkan oleh model yang sederhana dan elegan dari Albert Einstein dan Willem de Sitter tahun 1932 pada mana gravitasi lambat laun akan menghentikan laju pengembangan ruang.Meskipun demikian, semenjak pertengahan tahun 1980an sederetan pengamatan telah dilakukan yang mana hasilnya nampaknya tidak sesuai dengan teori standar. Hal ini menyebabkan sejumlah orang mengusulkan membangkitkan kembali konsep lama yang di sesali Einstein yaitu Konstanta Kosmologi agar supaya menjelaskan data baru ini lebih baik.
Konstanta ini pertama kali diperkenalkan oleh Einstein di tahun 1917 untuk mengimbangi gaya tarik gravitasi, karena beliau percaya akan alam semesta yang bersifat statik. He considered it a property of space itself, but it can also be interpreted as a form of energy that uniformly fills all of space; if lambda is greater than zero, the uniform energy has negative pressure and creates a bizarre, repulsive form of gravity. However, Einstein grew disillusioned with the term and finally abandoned it in 1931 after Edwin Hubble and Milton Humason discovered that the universe is expanding.
In 1987 physicists at the Lawrence Berkeley National Laboratory and the University of California at Berkeley initiated the Supernova Cosmology Project (SCP) to hunt for certain distant exploding stars, known as type Ia supernovae. They hoped to use these stars to calculate, among other things, the rate at which the expansion of the universe was slowing down.
Deceleration was expected because in the absence of lambda, many people thought that "ΩM", which is the amount of observable matter in the universe today as a fraction of the critical density, was sufficient to slow the universe's expansion forever, if not to bring it to an eventual halt.
In 1998, after years of observations, two rival groups of supernova hunters – the High-Z Supernovae Search Team led by Schmidt and Riess and the SCP led by Perlmutter – came to the conclusion that the cosmic expansion is actually accelerating and not slowing under the influence of gravity as might be expected.
The two teams came to this conclusion by studying type Ia supernova where they found that the light from over 50 distant supernovae was weaker than expected. This was a sign that the expansion of the universe was accelerating.
In order to account for the acceleration, about 75% of the mass-energy content of the universe had to be made up of some gravitationally repulsive substance that nobody had ever seen before. This substance, which would determine the fate of the universe, was dubbed dark energy.
It is now thought that dark energy constitutes around 75% of the current universe, with around 21% being dark matter and the rest ordinary matter and energy making up the Earth, planets and stars.
"The findings of the 2011 Nobel Laureates in Physics have helped to unveil a universe that to a large extent is unknown to science," stated the Academy. "And everything is possible again."
"My involvement in the discovery of the accelerating universe and its implications for the presence of dark energy has been an incredibly exciting adventure," says Riess. "I have also been fortunate to work with tremendous colleagues and powerful facilities. I am deeply honored that this work has been recognized."
New problems
Cosmologist Michael Turner from the University of Chicago says that the award to Perlmutter, Riess and Schmidt is "well deserved". "The two competing teams is a wonderful story in science – the physicists vs the astronomers," says Turner. "The biggest surprise to both teams was that the other team got the same answer. Each team believed the other didn't know what they were doing."Turner adds that before the discovery, cosmology was in some disarray with astronomers having a model of the universe based on cold dark matter and inflation, but with not enough matter to make the universe flat – a key prediction of inflation.
"Dark energy and cosmic acceleration was the missing piece of the puzzle," says Turner. "Moreover, in solving one problem, it gave us a new problem – what is dark energy? I think that is the most profound mystery in all of science."
Robert Kirshner from Harvard University who supervised both Schmidt and Riess when they were PhD students says the decision by the Nobel committee is "great" as it will mean "no more waiting". "We did a lot of foundational work at Harvard and my postdocs and students made up a hefty chunk of the High-Z Team," says Kirshner. "[Riess] did a lot after the initial result to show that there was no sneaky effect due to dust absorption and that, if you look far enough into the past, you could see that the universe was slowing down before the dark energy got the upper hand, about five billion years ago."
Kirshner adds that Perlmutter is also "very deserving" of the prize. "[Perlmutter] was persistent even when his programme was moving slowly and, despite getting a contrary result in 1997, was convinced of cosmic acceleration during 1998 by comparing his own extensive data set of distant supernovae with the nearby supernovae measured by the group in Chile."
Peter Knight, president of the Institute of Physics, which publishes physicsworld.com says the work has "triggered an enormous amount of research" on the nature of dark energy. "These researchers have opened our eyes to the true nature of our universe. They are very well-deserved recipients," says Knight.
Leading lights
Born in Champaign-Urbana, Illinois, in 1959, Perlmutter graduated from Harvard University in 1981 receiving his PhD from the University of California, Berkeley in 1986 where he worked on robotic methods of searching nearby supernovae. He then moved to the Lawrence Berkeley National Laboratory and the University of California, Berkeley. Perlmutter now heads the SCP based at Lawrence Berkeley National Laboratory.Schmidt was born in Missoula, Montana, in 1967. He graduated from the University of Arizona in 1989 and received his PhD from Harvard University in 1993 on using type II Supernovae to measure the Hubble Constant. During postdocs at Harvard, Schmidt, together with Nicholas Suntzeff from the Cerro Tololo Inter-American Observatory in Chile, formed the High-Z Supernovae Search Team. In 1993 Schmidt then went to the Harvard-Smithsonian Center for Astrophysics for a year before moving to the Australian National University where he is currently based.
Riess is also a former member of the High-Z Supernovae Search Team where he lead the 1998 study that reported evidence that the universe's expansion rate is now accelerating. He was born in Washington, D.C in 1969 and graduated from The Massachusetts Institute of Technology in 1992. Riess received his PhD from Harvard University in 1996 researching ways to make type Ia supernovae into accurate distance indicators. In 1999 he moved to the Space Telescope Science Institute at Johns Hopkins University.
Tidak ada komentar:
Posting Komentar